June 4, 2008

Statistics:

Initial Target: Grand Island, NE
Departure: Bolingbrook, IL 6:30 am
Arrival: Belleville, KS 11:30 pm
Intercepts: Kearney, NE
Tornadoes: 0
Hail: Non-Severe (not measured)
Wind: Non-Severe (not measured)
Features: RFB, Roll Cloud
Miles: 937

Summary:

Day before the big day, two day plains trips with Chad and Ben.  Targeted southeast Nebraska.  Intercepted messy severe warned cell near Ravenna, NE before dropping to Kearney and intercepting a supercell with very nice structure.  Observed rotating rain bands and large RFB before storm elevated and orphaned its base leaving a dramatic roll cloud.  Followed dieing storm east before stopping for dinner and then south across the KS border, punching a severe warned line, and stopping for the night in Belleville, KS.

Crew and Equipment:

Chase team included Chad Cowan and Ben Leitschuh.  Equipment: TH-F6A Tribander, and GPS/Cell Phone equipped laptop.  Photography by Skip Talbot.

Details:

I just quit my job midweek and a system was entering the plains on Thursday, which made it perfect for a two day trip out to the plains.  The day featured strong instability and great directional shear from a very deep surface over Colorado, but the speed shear was forecast to be on the light side.  This was the "day before the day" chase with Friday forecast to be a major outbreak.  Chad, Ben, and I left the suburbs bright and early and trekked west on 80 targetting  somewhere in southeast Nebraska.
We took a slight detour south of Des Moines after distracting Chad with maxed out forecasted tornado parameters.  As we crossed the Nebraska border and got back onto 80 near Grand Island, storms started to fire right  over head.  We went for more mature storms to our northwest that were already warned.  We caught a view of the base as we approached Ravenna:
There was heavy precipitation in the storm's updraft base, and it was exhibiting high precipitation supercell characteristics.  As it started to congeal into a line with other nearby cells, we dropped south towards Kearney for a more discrete storm.
Just south of Kearney, our storm's base came into view, and it was quite a sight.  The storm had a very large rain free base, brilliant contrast, and two areas of rotation.  The storm went tornado warned as we setup our tripods to shoot its approach.
Looking west:
Huge bell shaped meso:
As the supercell approached some rain curtains started to fall through the base.  Rotation was observed in these rain bands, just to the right of the telephone pole:
The rain free base approached from the west with amazing contrast:
The rear flanking downdraft cuts through the storm, bowing the the base out forward:
We let the base pass overhead and noted lots of churning motion, but no tight areas of rotation.  We got out ahead of the storm just across the river and stopped for more pictures of the base:
A bowl shaped bulge in the storm's updraft base:
We stayed ahead of the storm as it started to lose strength and its warnings.  The updraft tower starting to become elevated and evaporate away from the ground:
We stopped east of Kearney for more pictures.  The supercell completely abandoned its updraft base which had bowed out into more of a gust front, leaving behind a very dramatic roll cloud:
Looking west at the lifting storm and orphaned roll cloud below:
Looking southwest:
As the roll cloud spread out to the east, it too started to evaporate.  On the north end of it, however, strange tentacle like tendrils of cloud started to condense on the leading edge.  I had never seen anything like it before.
The tentacles appeared to be an inflow related feature, but I'm not entirely sure what processes are behind this unusual formation.
After stopping for some grub in Grand Island, a mean looking severe warned line started to go up on the NE/KS border.  We went south to intercept it, not expecting any tornado potential, just a good lightning show, and the lightning was indeed fantastic.  Punching through the line without encountering more than a smattering of pea sized hail, we stopped for the night in Belleville, KS.
Conclusion:

There were no tornadoes on this chase, but the supercell structure was fantastic, and it was a great opener to a two day event.  The storm we wound up targeting was in the middle of two more tornado clusters of storms, but southwest Iowa turned out to be the most prolific tornado producing area.

 

Lessons Learned:

  • Don't distract Chad with Rich Thompson's index when he's driving.